Recently, an associative memory with the minimum distance search function has drawn attention in the field of data processing and, particularly, in image compression and image recognition. An associative memory can match patterns for object recognition required in intelligent information processing or compressing data by use of data groups called codebooks.
An associative memory is one of representative functional memories having a function of searching for data most similar closest distance) to a series of input data search data) from a plurality of reference data stored in the associative memory. Due to its excellent search function, the associative memory has been expected to dramatically improve the performance of applications that have a pattern matching function, such as image compression and image recognition, as described above.
Typically, pattern matching locates data most similar to input data from R number of reference data having a W-bit width. Thus, an associative memory having a function of minimum distance search is involved in the core part of data processing, such as image compression and image recognition. In the past, for associative memories capable of fully-parallel minimum distance search, those having a function of Hamming, Manhattan or Euclid distance search have been suggested.
Until now, architectures with fully-parallel search capability for the minimum Hamming distance or for the minimum Manhattan distance have been suggested.
However, there is a problem with conventional associative memories since only one reference data closest to search data is output as a result of comparison between search and reference data, and thus, a plurality of reference data close to the search data cannot be outputted.
It is an object of the present disclosure to resolve the above problem by providing an associative memory capable of outputting multiple reference data close to the search data.
Another object of the present disclosure is to provide a search system comprising an associative memory capable of outputting multiple reference data close to the search data.